Warning: Spoilers for Stranger Things season 4, volume 1!
New creatures of the Upside Down were introduced through Stranger Things season 4, volume 1 in the form of Demobats. The threatening species served as secondary antagonists alongside the installment's main villain, Vecna. While Stranger Things has a tendency to debut new monsters from the Upside Down, the existence of Demobats presents the question of where they've been in the first three seasons.
As the world of the Upside Down started to bleed into the world of Hawkins after Eleven inadvertently opened a gate to the Upside Down, new threats emerged. First, it was the Demogorgon, a large bipedal creature, who wreaked havoc in Stranger Things season 1. The next season revealed more regarding a Demogorgon's lifecycle by showing in the pollywog and Demodog stage. The latter of which played a greater role as Demodogs were set loose in Hawkins while the season's main antagonist, the Mind Flayer, took control. The Mind Flayer, who also served as the primary antagonist in Stranger Things season 3, is the leader of the Upside Down. The «Shadow Monster,» as it's also called, is a sentient being made up of dust particles, but it has the power to control other beings within the Upside Down as well as human hosts.
Related: Stranger Things Season 4's Episode Lengths Are Ridiculous
While Vecna seems to do the Mind Flayer's bidding, causing severe problems for the group in Hawkins, the Demobats are also proving to be a problem. The large bat-like creatures are shown in Stranger Things season 4 near the Upside Down version of the Creel House. However, they aren't closely shown until «Chapter Six: The Dive,» when they drag Steve Harrington away from the «water gate.» Unlike
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